Why is the flash of lightning from clouds seen much before the thunder, although both occur simultaneously?
The velocity of light which is equal to 3 x 108 ms-1 is much greater than the velocity of sound equal to 344 ms–1. Hence, we see the flash of lightning much before the sound of thunder reaches us.
Which separation techniques will you apply for the separation of the following?
Butter from curd.
Write the steps you would use for making tea. Use the words—solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.
Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).
|
Substance Dissolved |
Temperature in K |
||||
|
283 |
293 |
313 |
333 |
353 |
|
|
Potassium nitrate |
21 |
32 |
62 |
106 |
107 |
|
Sodium chloride |
36 |
36 |
36 |
37 |
37 |
|
Potassium chloride |
35 |
35 |
40 |
46 |
54 |
|
Ammonium chloride |
24 |
37 |
41 |
55 |
66 |
Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.
|
Substance Dissolved |
Temperature in K |
||||
|
283 |
293 |
313 |
333 |
353 |
|
|
Potassium nitrate |
21 |
32 |
62 |
106 |
107 |
|
Sodium chloride |
36 |
36 |
36 |
37 |
37 |
|
Potassium chloride |
35 |
35 |
40 |
46 |
54 |
|
Ammonium chloride |
24 |
37 |
41 |
55 |
66 |
Find the solubility of each salt at 293 K. Which salt has the highest solubility at this temperature?
|
Substance Dissolved |
Temperature in K |
||||
|
283 |
293 |
313 |
333 |
353 |
|
|
Potassium nitrate |
21 |
32 |
62 |
106 |
107 |
|
Sodium chloride |
36 |
36 |
36 |
37 |
37 |
|
Potassium chloride |
35 |
35 |
40 |
46 |
54 |
|
Ammonium chloride |
24 |
37 |
41 |
55 |
66 |
Mock Test Series
